The best compression settings for rap vocals really depend on the situation and the goal you are trying to achieve. Broadly speaking, using faster attack times might contain the peaks of the vocal performance, but at the same time can make it sound unnatural and lifeless. Release depends strictly on the initial goal, if you want to even out all of the vocalist’s performance, use slower release. A faster release could be used to contain peaks. Use lower ratios and softer knee if you want your compression to be subtle, otherwise, try to use higher ratios and harder knee.
Best Compression Settings for Rap Vocals explained
Over the decades, hip-hop took a long journey and was reinvented several times by the legends of this genre. First, it was a sophisticated social statement of people who were disagreeing with the establishment at that time. Then it became an opportunity to express anger and disappointment about their everyday life and the problems that came with that. And finally, hip-hop became an art form with which you could express something deeply personal and perhaps even intimate.
Despite hip-hop having lots of flavors, there is one thing that is common for all of them. It is very hard to imagine a hip-hop track without aggressive and rhythmic rap vocals unless this track is instrumental. And as audio producers and engineers, we have a very important job of maintaining that explosive energy and at the same time containing it so it would be listenable on the record.
One of the main components to achieving that goal is, of course, properly applied compression. But there are a few things we could do even before we start compressing.
Sometimes audio engineers and producers have no control over the recording process and have to work with the stem tracks provided by the artist. In this case, there’s not much we could do but work with what we have. But if you actually supervise the recording process, there are quite a few things you could do to make your life easier as a mixing engineer.
Firstly, you have to choose the right microphone that has a proper dynamic response and suits best the vocalist’s timbre. It also would be rather beneficial if you have a vocal booth at your disposal. If you don’t own one or don’t have access to one, try to record in the room with as little reflections as possible. This will give you the clearest vocals possible and will save some crucial time later. If you don’t have a lot of microphones to choose from, take some time to learn how those that you use are behaving in certain situations or invest in a more diverse set of mics.
Secondly, always use pop filters and choose the right microphone placement and distance to the vocalist. If the vocalist is too close to the microphone, you will get a spike in low mid-range frequencies, which is called the proximity effect and will cause you a lot of trouble in mixing stages. If your vocalist is too far from the microphone, you will lose some essential clarity and initial attack of the vocal.
Finally, if you’re lucky enough to own some outboard gear, choose the right vocal chain for the recording. Applying some analog EQ with high-pass filters, tube preamplifier, and opto-compressor will make your rap vocals shine without any further processing. But if you don’t own any studio gear, you still have to invest in a decent audio interface with good preamps that can handle a “hot” signal.
A very important thing to remember is that very few effects serve the purpose of fixing things. In other words, there’s very little chance that you would fix a poorly recorded performance with a compressor. Listen to your recorded rap vocals carefully and critically, and if you are happy with a result, then you could begin compressing.
The biggest problem with compressors is that, unfortunately, no one can tell you the exact settings that would work in any given situation. So if someone tells you to use a specific ratio and a certain attack and release times for your rap vocals, there is a very little chance that those would actually work. Even if you use presets that come with your favorite compressor, those only meant to be a starting point. And you’d have to adjust it further. So instead of selling you some snake oil, we will try to give you a better understanding of compression and how each parameter will give you a benefit given that it is used properly.
Every compressor has its own unique flavor, and some are better for drums, for example, and others truly shine on vocals. That being said, there are no strict guidelines on which compressor to use in which situation. So you might as well stick with the one you are the most familiar with. For the purposes of this article, it wouldn’t really matter because we are covering the general principles of rap vocal compression, and no matter what compressor you would use, in one form or the other, you will find the same parameters. And those parameters would be attack, release, threshold, ratio, and knee.
The attack settings tell the compressor when to start compressing. Fast attack will compress the transients and might contain the bursts of energy at the start of every word in rap vocals. But at the same time, it might as well sound rather unnatural. So you may consider slower attack times. It all very well depends on the actual performance of the vocalist and at what result you are aiming.
As a starting point, you can set your attack around 30-50 ms and see where it will get you. If your vocals still feel a bit spiky, you may set your attack to be a bit faster. If the performance already has a lot of bursts, set your attack to 20 ms and go from there.
Release settings tell your compressor when to stop working. When it comes to rap vocals, setting a release is rather a tricky thing since you want your vocals to be as rhythmic as possible and go with the flow of the track. Generally speaking, you want every word in the performance of the vocalist to be evenly heard. So listen where the ending of the words starts to decay and set your release accordingly.
Unfortunately, there are no specific numbers we can give you even as a starting point. The only thing we could tell you is that your compressor will need some time to work, so the difference between attack and release times should be significant. Unless the only thing you are trying to achieve is containing the spikes.
With threshold, you can tell your compressor at which volume of the input signal it should start to work. So naturally, if you want to contain the peaks, set your threshold a few dB lower than the maximum input. If your goal is to even the overall performance, set the threshold significantly lower. In most cases, you are looking for 3-6 dB of gain reduction. More than that wouldn’t be really beneficial, and less isn’t significant enough in terms of rap vocals.
The ratio shows how much quieter the compressed signal would be than the original one. For example, if your ratio is 6:1, that means that the compressed signal would be 6 dB quieter over each dB over the threshold. There are two ways to approach this particular situation. Firstly, you could do the math yourself and figure out what ratio to use, considering that you are looking for approximately 6 dB of gain reduction and want only to contain peaks. Secondly, you can set it to your taste, knowing that lower ratios would give you more subtle compression, and higher ratios would make it more obvious.
The knee shows us the relation between the initial and compressed signals. A hard knee will make the transition between those two signals very fast and obvious. Soft knee, on the other hand, will make it very subtle and unnoticeable. As a general rule, when it comes to vocals, you want compression to be subtle and your voice to sound as natural as possible. So a softer knee would be a better choice.